蒙库铁矿巷道围岩应力测试及数值分析

Test and Numerical Analysis of Tunnel Surrounding Rock Stress of Mengku Iron Mine

蒙库铁矿884 m水平开拓系统在掘进的过程中部分地段发生了冒顶、坍塌、片帮等地质灾害,为了掌握884 m主运输平硐所在区域的水平应力情况,首先在巷道内部进行了工程地质调查与测绘,经共轭剪节理极射赤平投影分析,确定巷道最大主应力在NE26.5°方向;同时,在不同巷道进行了6处围岩应力测试,测试成果显示其实测水平应力在10 MPa^20 MPa之间,水平应力的平均值为16 MPa。通过对巷道围岩的受力与变形状态的数值模拟,得出在较高应力水平作用下,开挖后的巷道顶部竖向位移最大值约为0.10 m,水平位移最大值约为0.15 m,水平压应力最大值约为17.5 MPa,为巷道围岩稳定性分析与支护结构设计提供了可靠的围岩应力参数,对类似巷道工程支护具有指导意义。

In the development system 884 m of Mengku iron during its tunneling process there were collapse,roof fall,spalling and other geological disasters happened,in order to know horizontal stress of the 884 m main transport adit area, the engineering geological survey and mapping were first introduced in the roadway, by stereographic projection analysis of the conjugate shear joints,it is determined that the maximum principal stress in roadway is at NE26. 5° direction; at the same time,in 6 different roadway surrounding rock stress testing,test results show that the horizontal stress is in range of 10 MPa ~ 20 MPa,the average horizontal stress is 16 MPa. Through the numerical simulation of stress and deformation state of roadway surrounding rock,under a higher stress level,the maximum displacement at the top of tunnel after excavation is about 0. 10 m,the maximum horizontal displacement is about 0. 15 m,the maximum horizontal compressive stress is about 17. 5 MPa,and provides a reliable stress value of surrounding rock for the design of supporting structure and stability analysis,it has guiding significance to supporting of similar tunnel projects.